Electric apparatus



J. J. FRANK.

ELECTRIC APPARATUS.

APPLICATION man APR.25. 1919.

1,376,01 1 Patented Apr 26, 1921.

Inventor John J.T 'r-ank,

b f/ 4920M:

His ttornes.

UNITED STATES PATENT OFFICE.

JOHN J. FRANK, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION 01 NEW YORK.

ELECTRIC APPARATUS.

Specification of Letters Patent- Patented Apr. 26, 1921.

Application filed April 25, 1919. Serial No. 292,609.

T 0 all whom it may concern:

Be it known that I, JOHN J. FRANK, a citizen of the United States,residingat Pittsfield, in the county of Berkshire, State ofMassachusetts, have invented certain new and useful Improvements inElectric Apparatus, of which the following is a specification.

My invention relates to electrical apparatus comprising wholly or inpart a winding. ()ne object of my invention is to provide suchelectrical apparatus in which the reactance and the stresses due to themagnetic action are uniform in their distribution, or more nearlyuniform than heretofore. Another object of my invention is to provide animproved high current winding, and electrical apparatus comprising ahigh current winding, having taps whereby the voltage of the highcurrent winding may be varied with a minimum unbalancing of thereactance and of the stresses due to the magnetic action. Still anotherobject of my invention is to provide a method of operating an electricalwinding whereby the reactance and the stresses due to the magneticaction are continued uniform, or more nearly uniform than heretofore, asthe number of operating turns is increased or diminished.

My invention is particularly applicable to electrical apparatuscomprising wholly or in part ahelical winding wherein a plurality ofconductors are disposed one outside another in coil groups, and also isparticularly applicable to transformers in which there are a pluralityof windings. It will be understood, however, that my invention is notlimited to such a winding or to such a device, but from a broader aspectcomprehends as well any other winding and any other apparatus in whichthere is a winding in which conductors in different coil groups are, ineffect, connected in series to form a plurality of lots of seriesconnected conductors traversing the same coils.

My invention will be understood most readily from the accompanyingdrawing and following description wherein I have illustrated anddescribed in some detail the best embodiments of my invention of which Iam now aware. Figure 1 is an outline elevation of a transformerembodying my invention. Fig. 2 is a perspective view of the low voltage,high current, windingof the device of,

Fig. 1; while Fig. 3 is 3. dia rammatic vie illustrating the mode ofciinnections 811i ployed in Fig. 2.

ln the transformer of Fig. 1, the core is provided with a winding leg 2.about which are placed the windings. The windings of the transformerillustrated comprises a high voltage winding and a low voltage windingthe low voltage winding illustrated is of helical type and is adaptedfor currents of yery high value. The high voltage winding is made up oftwo sections 3 and 4, each section comprising three disk coils of afamiliar type. These two sections 3 and 4 are separated, and one sectionis disposed at each end of the low voltage winding 5. It is immaterialto my invention how'the coils of the two sections-3 and 4 are connectedbut for the purpose of the present explana tion of my invention they maybe considered to be connected in series. The construction of the lowvoltage, high current, winding 5 will be better understood from Fig. 2.

As appears especially from Fig. 2, the low voltage winding 5 is in theform of a helix. Five conductors 10, 11, 12, 13 and 14, dis posed oneabove another radially. or one outside another radially (14 being at theinside of the winding and 10 at the outside thereof), are carried in theform of a continuous helix from one end of the low voltage winding tothe other end thereof. Each turn of the five conductors forms inefli'eot a coil or coil group of a plurality of conductors, these coilgroups 16, 17, 18, 19 and 20 being separated from each other, as appearsfrom both ig. 1 and Fig. 2, for the purpose of providing ventilatingspaces whereby the heat ge'nerated within the conductors 10-14 is morereadily dissipated. The conductors 10-14 are insulated from each otherand are connected in series by cross connectors later described andwhich may be observed at the right of Fig. 2; a tap is brought outadjacent each cross connector whereby one or any other number of theseconductors may be used to convey current in series. It will be observedthat each of the conductors 10-14 is carried, as it were, through everycoil or coil group of the winding; in effect, as windings are more com:monly considered, each of the plurality of conductors of each coil isconnected in series with the similarly located conductors in the othercoils whereby lots of series connected conductors are provided in thedrawing, conductor 10 forming one lot. conductor 11 a second lot, etc.(fine (and in carrying out the method of my invention, the most commonlyused) of the terminals of Fig. 2 is terminal 25 which is connecteddirectly to conductor 12; as will be seen especially from Fig. .2, andas before indicated, conductor 12 occupies or constitutes the centrallayer and turn of each coil group. Terminal 25 is connected to the lowerend of the conductor 12, and the upper end of conductor 12 is connectedto tap 26. A terminal or connection board 27, suitably supported fromthe core 1, is provided for supporting in proper relation terminal 25,tap 26, and the other taps and terminals hereinafter described inconnection with winding 5. Terminal 26 comprises also, or is attachedto, connector 29 through which the upper end of conductor 12 isconnected to the lower end of conductor 11. This connector 29 (like theother connectors hereafter mentioned) extends across the face of the lowvoltage winding 5, that is external to the same and from one end of thewinding 5 to the other end thereof. The opposite end of conductor 11 isconnected to tap 30, resembling tap 26, and connector 31. like connector29, connects the upper end of conductor 11 to the lower end of conductor13. It will be noted that the two conductors 11 and 13 are at oppositesides of conductor or layer 12 and are, radially, the nearest conductorsand layers to the more central layer 12. The upper end of conductor 13is connected to tap 32 and by connector 33 is connected to the lower'endof conductor 10. Again it should be noted that conductors 10 and 13 areat opposite sides of the central layer or conductor 12. The upper end ofconductor 10 is connected to tap 34 and by means of connector 35 isconnected-to the lower end of the'remaining conductor and the conductoror the opposite side of and symmetrically related to conductor 12,namely, conductor 14. The upper end of conductor 14 is connected toterminal 36. Accordingly it will be seen that by using the appropriatetaps and terminals, a circuit may be completed from the line through oneor any other number of the conductors or layers lO-14 of this wind- 1n%lurrent through a winding produces magnetic action which in turnresults in mechanical stresses in the winding itself, in any adjacentcore, and in any'adj acent'winding also carrying current. In order thatthese mechanical stresses may be resisted or neutralized,- it isdesirable that they be uniformly distributed over the whole faces of thecoils or coil groups so far as possible, or in other words, that theyappear as though originating from the mean or central turn or layer ofeach coil; it is also desirable that the magnetic center of the windingcontinue at the same point when different numbers of conductors arecarrying current. My invention as thus described provides a winding inwhich these results may be obtained although the number of operatingconductors be changed, and also provides a winding in which thereactance or action of the winding 5 by reason of leakage magnetic fiux,is substantially constant in distribution and varies only inintensity asthe number of operating conductors is changed. The method of myinvention as employed with this or any other suitable winding, securesthe desired results.

The mode of practising my invention will be understood from thefollowing description of the preferred method of operation of winding 5Suppose that it is desired that all five of the conductors 1014 beoperated in series; in such a case the line receiving energy from, ordelivering energy to, the winding 5 is connectedto the two terminals 25and 36. It will be observed that the circuit in the winding 5 is thencontinuous from the ter minal 25 and lower end of conductor 12, throughconductor 12, connector 29 to the lower end conductor 11, and thencethrough the remaining connectors and conductors to the terminal 36. If,now, it' is necessary to reduce the number of operating conductors inthe winding by one, the line is continued in connection with terminal 25but the connection to terminal 36 is broken and connection made to tap34. It will be seen that with this connection only conductors or layers10, 11, 12 and 13 are in operation and carrying current and theseconductors (in the present instance) are in series as before; conductoror layer 14 carries no current and hence is out of operation. It will beobserved that whereas with all five of the conductors in series themagnetic center of the winding is located at substantially the center ofthe axis of the whole winding, the magnetic center with only fourconductors in series is likewise located at substantially the center ofthat axis; in other words, since the active length of the winding isconstant irrespective of the number of conductors in operation, andsince all conductors have the same axis, the magnetic center of thewinding remains substantially stationary as the number of active turnsis varied. It should be also observed that whereas with all fiveconductors in series, the stresses on the face of each coil group due tothe magnetic action and reaction are substantiall concentrated, as itwere, in or along the l1ne of the center of the conductor or layer 12,with only four conductors in operation the stresses are shifted only tosubstantially the line of the outside edge of the conductor or layer 12,which it will be noted is but a 1.sve,o11

very small shift. Also it may be seen that the reactance or action ofthe leakage flux is also substantially the same (except for intensity ofeffect) whether the five conductors are active or whether only the fourconductors are in operation. If it is necessar to still further reducethe number of actlve conductors by one, the connection to tap 34 isbroken and the corresponding connection made to tap 32. With thisarrange ment the circuit is completed through conductors or layers 12,11, and 13 only, and in that order counting frolnterminal 25. Again itmay be observed that with only these three conductors in operation, thereactance and the stresses due to magnetic action of and on the winding5 are almost the same as before (except perhaps in degree) and indeedare now very closely if not indeed exactly like the reactance andstresses of the original connection of all five conductors in series. Itwill be observed that in reducing the number of active conductors, I doso by cutting out so far as possible, conductors or. layers similarlylocated at op posite sides of the more central layer or layers of thewinding, and cutting out each time those active conductors or layerswhich, radially, are farthest removed from the central layer or layers.Thus the conductor or layer 12 being the most central layer of thewinding, when it is necessary to reduce the number of conductors by oneI cut out one of the conductors or layers'farthest removed from theconductor 12, namely conductor 14 in the first instance above. Whenagain it is necessary to reduce the number of active conductors I againout the active conductor or layer farthest removed from 12, and theactive conductor located similarly to conductor 14 but on the oppositeside of la er 12, namely conductor or layer 10. WV henever it ispossible to reduce the number of layers or conductors by two, Isimultaneously cut out those two layers at opposite sides of andfarthest removed from the central layer or conductor 12, such asconductors 10 and 14. If the number of operating conductors is to bereduced still further, I continue to pursue the same plan and first cutout conductor 13, and thereafter conductor 11; there being but fiveconductors or layers in the winding illustrated, the number ofconductors or layers in this winding cannot be further reduced sincethere now remains in operation only one conductor or layer, namelyconductor 12. The opposite portion of my method and the contemplatedoperation of winding 5, may be understood from what has gone before; ina few words, it consists in increasing the number of conductors inoperation by causing the current to traverse in addition to thoseconductors or layers already in service, a sufiicient number of thoselayers or conductors of the winding which, radially, are next nearestthe more central layer or conductor and I layer or conductor. Thus withthe current traversing only the conductor or layer 12, layer orconductor 11 is first added, thereafter layer or conductor 13, thenconductor 10 and finally conductor 14:, or only so many of theseconductors or layers in the order named, as may be necessary-to satisfythe immediate conditions.

While I have illustrated in the accompanying drawing and described abovethe best embodiments of my invention of which I am now aware, it will'beunderstood that these embodiments are merely illustrative of myinvention and that my invention is not limited thereto but is set forthin the following claims.

WVhat I claim as new and desire to secure by Letters Patent of theUnited States, is

1. A winding comprising a plurality of coil groups in which conductorsin each group are disposed one outside another radially and connectedrespectively in series with conductors in another coil group to formlots of series connected conductors, the lots being connected in seriesand taps for the windings being provided between each lot of conductors.

2. A winding comprising a plurality of coil groups in which a pluralityof conductors in each group are disposed one outside anotherradially'and each of said plurality of conductors of each of said coilgroups is connected in series with the similarly located'conductors inthe other of said coil groups to form lots of conductors, the lots ofconductors being connected in series and taps for the winding. beingprovided between each lotvof conductors.

'3. A winding comp-rising a plurality of coil groups in which aplura-llty of conductors in each group are disposed one outside anotherradially, the winding being distinguished by each of the said pluralityof conductors of each coil group being connected in series withconductors similarly located in the other coil groups to form lots ofconductors, the lots of conductors being so connected in series that oneterminal of the winding is at one end of the lot adjacent the center ofthe coil groups, and taps for the winding being provided between eachlot of conductors.

4:. A winding comprising a plurality of conductors disposed as a helixand one outside another radially, a conductor near the center of thecoil groups providing one terminal of the winding, a connector from theopposite end of said conductor connecting the said conductor in serieswith a conductor at one side thereof, a connector connecting said secondconductor in series with a conductor at the opposite side of the firstmentioned conductor, and a tap for the winding connected theretoadjacent the first mentioned connection.

5. A winding comprising an odd number of conductors disposed as a helixand outside another radially,the center conductor providing one terminalof the winding, a. connector from the opposite end of said conductorconnecting the said central conductor in series with a conductorimmediately at one side thereof, a connector connectin said secondconductor series with a 'con uctor immediately at the opposite side ofthe central conductor, other connectors completing the series connectionof the conductor of the winding by similarly cross connecting pairs ofconductors at opposite sides of the center conductor, and taps for thewindings connected thereto adjacent each connector.

6. A winding comp-rising a plurality of coil groups in which conductorsin each group are connected in series with conductors in another coilroup to form lots of series connected con uctors, connectors extendingfrom one end of the winding to the other connecting said lots ofconductors in series, and taps for the windings connected theretoadjacent each connector.

7. Electrical apparatus comprising a core, a winding thereon, and asecond Winding on said core inductively related to the first mentionedwinding, said second winding comprising a plurality of coil groups inwhich conductors in each group are connected in series with conductorsin another coil group to form lots of series connected conductors,connectors extending from one end of the winding to the other connectingsaid lots of conductors in series, and taps for the windings connectedthereto adjacent connectors.

In witness whereof, I have hereunto set my hand this 23rd day of April,1919.

JOHN J. FRANK.

